我来帮你一步步搞定这两个问题——先修正语法错误，再处理SSL/TLS的连接问题：

一、先修复代码里的语法错误 #

你的原始代码有几处语法问题，我给你标出来并修正：

• 字符串类型的变量（比如$loginurl和$method）必须用引号包裹，PowerShell才会识别为字符串
• Invoke-RestMethod返回的是解析后的响应对象，没有RawContent属性；如果需要获取原始响应内容，应该用Invoke-WebRequest

修正后的基础代码如下：

$loginurl = "https://education.org/logon"
$data = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$data.Add('username','abc')
$data.Add('password','abc')
$method = "POST"
# 如果需要原始响应内容，用Invoke-WebRequest
$response = Invoke-WebRequest -Method $method -Uri $loginurl -Body $data
$response.RawContent

# 如果只需要解析后的响应数据，用Invoke-RestMethod
# $response = Invoke-RestMethod -Method $method -Uri $loginurl -Body $data
# $response

二、处理SSL/TLS连接错误（对应curl的--insecure参数） #

curl的--insecure参数是用来跳过SSL证书验证的，在PowerShell里可以通过两种方式实现：

方法1：启用更兼容的SSL/TLS协议版本 #

有些网站可能只支持旧版的TLS协议，而PowerShell默认的协议可能不兼容，你可以先设置允许使用TLS 1.2/1.3：

# 设置支持TLS 1.2和1.3
[Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12 -bor [Net.SecurityProtocolType]::Tls13

方法2：跳过SSL证书验证（完全对应--insecure） #

如果网站的证书本身无效（比如自签名证书），可以通过自定义证书回调来跳过验证，但注意：这会带来安全风险，仅在测试或信任的环境中使用：

# 创建跳过证书验证的回调
add-type @"
using System.Net;
using System.Security.Cryptography.X509Certificates;
public class TrustAllCertsPolicy : ICertificatePolicy {
    public bool CheckValidationResult(
        ServicePoint srvPoint, X509Certificate certificate,
        WebRequest request, int certificateProblem) {
        return true;
    }
}
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy

整合后的完整代码 #

把上面的设置和修正后的请求代码结合起来，就是能正常运行的版本：

# 先处理SSL/TLS相关设置
[Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12 -bor [Net.SecurityProtocolType]::Tls13
add-type @"
using System.Net;
using System.Security.Cryptography.X509Certificates;
public class TrustAllCertsPolicy : ICertificatePolicy {
    public bool CheckValidationResult(
        ServicePoint srvPoint, X509Certificate certificate,
        WebRequest request, int certificateProblem) {
        return true;
    }
}
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy

# 执行请求
$loginurl = "https://education.org/logon"
$data = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$data.Add('username','abc')
$data.Add('password','abc')
$method = "POST"
$response = Invoke-WebRequest -Method $method -Uri $loginurl -Body $data
$response.RawContent

内容的提问来源于stack exchange，提问作者Vivek Sharma